• Food Engineering Progress
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• v.23 no.2
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• pp.87-93
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• 2019

Temperature distribution studies were performed in steam-air retort to investigate the influence of various processing conditions (come-up time, sterilization temperature, and internal pressure throughout the steam-air retort). Retort temperature data were analyzed for temperature deviations during holding phase, maximum temperature difference between test locations at the beginning and after 1, 3, and 5 min of the holding phase, and box-and-whiskers plots for each location during the holding phase. The results showed that high sterilization temperature led to a more uniform temperature distribution than low sterilization temperature (pasteurization). In pasteurization condition, the temperature stability was slightly increased by increasing pressure during the holding phase. On the other hand, the temperature stability was slightly decreased in high sterilization temperature condition. Programming of the come-up phase did not affect the temperature uniformity. In addition, the slowest cold spot was found at the bottom floor during the holding phase in all conditions. This study determined that the temperature distribution is affected by retort processing conditions, but the steam-air retort needs more validation tests for temperature stability.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.373-380
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• 2023

This study surveyed and compared the temperature distribution in domestic refrigerators and freezers used in Korea to determine whether temperature varied according to the location of food storage. We selected 50 people to collect temperature data; among them, 25 measured the temperature of refrigerators, while the remaining measured the temperature of freezers. Consequently, the lowest and highest temperatures measured in domestic refrigerators were found to be -8.2℃ and 15.8℃, respectively, with an average temperature of 3.73℃. The temperature distribution based on internal location was: 5.06±1.69℃ for the door storage compartment, 4.18±1.19℃ for the inside wall surface, and 3.41±1.36℃ for the inner storage box. Significant temperature differences between the top and bottom were only identified at the door storage compartment (P<0.01). Further, the minimum and maximum temperatures measured in the freezer was -30.3℃ and 0.7℃, respectively, with an average temperature of -17.95℃. The temperature distribution based on location was: -17.19±1.68℃ for the door storage compartment, -17.81±1.07℃ for the inside wall surface, and -18.78±1.72℃ for the inside storage box. The results were similar to that of the refrigerator, with the lowest temperature in the inside storage box, and a significant temperature difference between the top and bottom noted only at the door (P<0.01). The maximum temperature difference (between locations) within the refrigerator and freezer was found to be 2.18 and 2.02℃, respectively. In conclusion, the temperature in the entire space was not constant; there were significant deviations at different storage locations. Therefore, public authorities should actively advise customers on the recommended storage locations for each food type. People will benefit from awareness about storage management, including avoiding storage of temperature-sensitive foods in door compartment.

• The Journal of Korean Academy of Prosthodontics
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• v.17 no.1
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• pp.23-34
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• 1979

In this study, the adhesive strength of three commercial polycarboxylate cements to ten types of dental casting alloys, such as gold, palladium, silver, indium, copper, nickel, chromium, and human enamel and dentine were measured and compared with that of a conventional zinc phosphate cement. The $8.0mm{\times}3.0mm$ cylindrical alloy specimens were made by casting. The enamel specimens were prepared from the labial surface of human upper incisor, and the dentine specimens were prepared from the occulusal surface of the human molar respectively. Sound extracted human teeth, which had been kept in a fresh condition since, extraction, were mounted in a wax box with a cold-curing acrylic resin to expose the flattened area. The mounted teeth were then placed in a Specimen Cutter (Technicut) and were cut down under a water spray, and then the flat area on the all specimens were ground by hand with 400 and 600 grit wet silicone carbide paper. Two such specimens were then cemented together face-to-face with freshly mixed cement, and moderate finger pressure was applied to squeeze the cement to a thin and uniform film. All cemented specimens were then kept in a thermostatic humidor cabinet regulated at $23{\pm}2^{\circ}C.$ and more than 95 per cent relative humidity and tested after 24 hours and 1 week. Link chain was attached to each alloy specimen to reduce the rigidity of the jig assembly, and then all the specimens were mounted in the grips of the Instron Universal Testing Machine, and a tensile load was delivered to the adhering surface at a cross head speed of 0.20 mm/min. The loads to which the specimens were subjected were recorded on a chart moving at 0.50 mm/min. The adhesive strength was determined by measuring the load when the specimen separated from the cement block and by dividing the load by the area. The test was performed in a room at $23{\pm}2^{\circ}C.$ and $50{\pm}10$ per cent relative humidity. A minimum of five specimens were tested each material and those which deviated more than 15 per cent from the mean were discarded and new specimens prepared. From the experiments, the following results were obtained. 1) It was found that the adhesive strength of the polycarboxylate cement to all alloys tested was considerably greater than that of the zinc phosphate cement. 2) The adhesive strength of the polycarboxylate cements was superior to the non precious alloys, such as the copper, indium, nickel and chromium alloys, but it was inferior to the precious gold, silver and palladium alloys. 3) Surface treatment of the alloy was found to be an important factor in achieving adhesion. It appears that a polycarboxylate cement will adhere better to a smooth surface than to a rough one. This contrasts with zinc phosphate cements, where a rough helps mechanical interlocking. 4) The adhesion of the polycarboxylate cement with enamel was found superior to its adhesion with dentine.

• Journal of Veterinary Clinics
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• v.16 no.2
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• pp.375-380
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• 1999

This study was conducted to develop an intrauterine inseminator (IUI) to deposit of frozen semen into uterus and to evaluate the results obtained after artificial insemination by IUI. Two Japanese spitzs (2 to 4 years of age) were used as semen donors. Semen was collected by manual masturbation into sterile glass collection tubes and separated into 3 fractions with only the sperm-rich fractions retained for further examination. Sperm motility >70%, sperm concentration of 200 to $400{\times}10^6 cells/ml$$\times$g for 5 min and poured out the suspended solution, and then diluted with 2 ml Tris-buffer which was consisted of 2.4 g Tris, 1.4 g citric acid, 0.8 g glucose, 0.1 $\mu\textrm{g}$/ml streptomycin, 100 IU/ml penicillin, 20 ml egg yolk to 100 ml mili-Q water (Ext I) or supplemented with 8 ml glycerol and 1 ml Equex STM paste to 100 rnl (Ext II). The diluted semen was cooled to 5$^{\circ}C$ in cold room, where the temperature in the sample reached 5$^{\circ}C$. Two h after beginning the cooling procedure, 2 ml of Ext II, also at 5$^{\circ}C$, was added and mixed by gently reversing the tubes several times during 1 h. The final sperm concentration for freezing was approximately $50{\times}10^6 cells/ml$. After equilibration, the semen was loaded into 0.5 ml straw and frozen on the liquid nitrogen vapour in styrofoam box. The straws were thawed at 7$0^{\circ}C$ for precisely 6 sec. After thawing of each straw, the frozen semen can survived over 50% motility. All the females were inseminated twice with 1 ml of $25{\times}10^6 cells/ml$

• Food Science and Preservation
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• v.23 no.4
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• pp.471-478
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• 2016

For the distribution of fresh produce, the thermoelectric cooling system combined with thermo electric materials (TEM) and phase change material (PCM) was studied. The PCM used this study was produced by in-situ polymerization technology which referred microencapsulation of hydrocarbon (n-tetradecane and n-hexadecane). In this study, quality characteristics of bell peppers in thermoelectric cooling system combined with TEM and PCM were analyzed and control was placed in an EPS (expanded polystyrene) box. As a result of quality characteristics analysis, weight of bell peppers decreased and moisture content of bell peppers was 90.96~94.43% during storage. Vitamin C content of bell pepper decreased during storage and reduction ratio of control was higher than that of BPT-5 treatment(bell pepper in thermoelectric cooling system with PCM which is kept the temperature at $5^{\circ}C$). The result of color value, on 21 day, ${\Delta}E$ value of BPT-5 treatment was 5.05 while that of control was 41.8. On 21 day, total bacteria count of BPT-5 treated bell pepper shown less than that of control. In conclusion, it suggested that the thermoelectric cooling system combined with PCM improved quality of fresh produce during transportation and storage.

• Publications of The Korean Astronomical Society
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• v.24 no.1
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• pp.53-64
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• 2009

MIRIS is the main payload of the STSAT-3 (Science and Technology Satellite 3) and the first infrared space telescope for astronomical observation in Korea. MIRIS space observation camera (SOC) covers the observation wavelength from $0.9{\mu}m$ to $2.0{\mu}m$ with a wide field of view $3.67^{\circ}\times3.67^{\circ}$. The PICNIC HgCdTe detector in a cold box is cooled down below 100K by a micro Stirling cooler of which cooling capacity is 220mW at 77K. MIRIS SOC adopts passive cooling technique to chill the telescope below 200 K by pointing to the deep space (3K). The cooling mechanism employs a radiator, a Winston cone baffle, a thermal shield, MLI (Multi Layer Insulation) of 30 layers, and GFRP (Glass Fiber Reinforced Plastic) pipe support in the system. Optomechanical analysis was made in order to estimate and compensate possible stresses from the thermal contraction of mounting parts at cryogenic temperatures. Finite Element Analysis (FEA) of mechanical structure was also conducted to ensure safety and stability in launching environments and in orbit. MIRIS SOC will mainly perform Galactic plane survey with narrow band filters (Pa $\alpha$ and Pa $\alpha$ continuum) and CIB (Cosmic Infrared Background) observation with wide band filters (I and H) driven by a cryogenic stepping motor.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.3
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• pp.289-303
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• 2007

This report includes basic data on nutrition education for Chinese adolescents living in Korea. A total of 183 Chinese adolescents living in Incheon participated in the survey. Body composition was analyzed by the Inbody 4.0., and questionnaires on personal dietary behavior were administrated. When compared with the body measure indices of Korean adolescents, we found that height was similar, but weight greater ($5{\sim}12 kg$) among the participants. Regarding obesity, 30.0% of all students were obese (BMI>25), especially the high school boys (42.0%). But in the case of middle school boys, the rates of obesity and under weight (BMI<18.5) were the same (both of them at 22.9%). The average WHR (Waist Hip Ratio) of the female high school group (0.9) was over the normal range. The average percent body fat for each group was also over the normal range. The percentage of students having breakfast everyday was 52.2%, and the rate of skipping breakfast was 25.0%. In the obesity group, the rate of skipping breakfast was remarkably high (P<0.05). Because lunch service was not available at the schools, a lunch box from home was the most popular pattern (43.1 %), but eating out was also popular at 36.6%. For the male high school students, the eating out rate was 62.8%. Since many have-lived in Korea for a few generations, the students' eating practices were much closer to the Korean pattern. For their ordinary meal pattern, 96.0% of the students included Korean foods. however, for New Years Day, the rate of having Gyo-Ja was 75.2%, and having Wol-Byung at Choo-seok was 78.6%, showing that the Chinese tradition still remains. In the case of food preferences, the percentage having Kimchi everyday was 62.1 %, but those drinking green tea was 13.1 %. For cold drinks, the rate for drinking them more than twice per week was 71.6%. The most preferred cooking method was frying with oil (50.6%). Among the students who had visited China (or Taiwan), the rate for 'bad food familiarity' was 37.0%, and the rate for 'did not know Chinese traditional course menus' was 71.3%. As a result of combining eating practices from both China and Korea, and the absence of lunch service in Chinese schools, students are showing bad dietary behaviors. therefore, it is necessary to provide proper nutrition education and a system for lunch service in Chinese schools.

• The Journal of Engineering Geology
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• v.25 no.1
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• pp.93-102
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• 2015

The characteristics of frozen soils are one of most important factors for foundation design in cold region. The objective of this study is to evaluate the shear strength and stiffness of frozen soils according to the confining conditions during the freezing and shearing phase. A direct shear box is constructed for the frozen specimens and bender elements are mounted on the wall of the shear box to measure shear wave velocities. Specimens are prepared by mixing sand and silt with a silt fraction of 30% in weight and the degree of saturation of 10%, giving a relative density of 60% for all tests. The temperature of the specimens in the freezer is allowed to fall below -5℃, and then direct shear tests are performed. A series of vertical stresses are applied during the freezing and shearing phase. Shear stress, vertical displacement, and shear wave along the horizontal displacement are measured. Experimental results show that in all the tests, shear strength increases with increasing vertical stress applied during the freezing and shearing phases. The magnitude of the increase in shear strength with increasing vertical stress during shearing under fixed vertical stress in the frozen state is smaller than the magnitude of the increase in vertical stress during freezing and shearing. In addition, the change in shear wave velocities varies with the position of the bender elements. In the case of shear waves passing through the shear plane, the shear wave velocities decrease with increasing horizontal displacement. This study provides an evaluation of the properties of shear strength and stiffness of frozen soils under varied confining condition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.554-564
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• 2017

The purpose of this study is to assist farmers in determining the optimal time for the shipment of stored apples by investigating the market trends, storage status and release dates of low-temperature stored apples. We surveyed 300 apple cultivation farms in Daegu, Gyeongbuk Province, which is the main producer of apples, and examined the cultivars, cultivation areas, storage conditions, and shipment status of apples. The main results are as follows: the proportion of apples cultivatedat different ripening times was surveyed. According to the results, the proportions of early, middle and late varieties were 78.3%, 63.7% and 96.0%, respectively. Also, 48.7% of the farm households surveyed had cold storage facilities. The average storage cost per apple box(15kg) was 978.3 won for self-storage and 1,771.8 won for consignment storage. For the six(6) months between November and April, the proportion of shipped apples was 91.6% of the total stored apples. The (average total?)annual apple shipment, including apples stored in general storage warehouses, was 744.4 boxes. The (average total?) annual shipment of cold storage apples was 616 boxes. The stored apples were mainly shipped to 'wholesale markets', which have the highest sales share, followed by 'production site collectors' and then 'supermarkets'. The most common shipping method of the apples was by general trucks, followed by low-temperature trucks, and finally by delivery services. The analysis of the factors influencing the decision to release apples by period showed that it was affected by the storage cost, loss rate, and customary shipping in the off-season(from May to August). On the other hand, in the general release season(from November to April), the statistically significant decision factors for the release of apples were the future expected price, storage cost and decision of the leading farmer groups. For farmers with a high share of general shipment, the deciding factors for the release of apples were the future expected price, storage cost, high income expectation, and decision by leading farmers.

• Applied Microscopy
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• v.7 no.1
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• pp.21-43
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• 1977

This experiment was undertaken in order to localize the labeled dbcAMP (dibutyryl cyclic AMP) in oocytes whose development has been suppressed by cold dbcAMP for 6 or 19 hours in vitro. Mouse oocytes were obtained from the ovaries of 3-4 week old A strain female mice, by puncturing the Graafian follicles in the modified Krebs-Ringer bicarbonate salt solution under the dissecting microscope. Those oocytes which have intact germinal vesicle were cultured in the basic culture medium supplemented with 0.4% bovine serum albumin (BSA). Cultivation of the oocytes was carried out in a microtube developed by Cho (1974). The cultures were then incubated in a humidified 5% $CO_2$ incubator maintained at $37^{\circ}C$ for 6 or 19 hours (Donahue, 1968). DbcAMP was added to culture medium for a final concentration of 100ug/ml, and $^3H-dbc$ AMP (specific activity 13 Ci/mM) for a final concentration of $40{\mu}Ci/ml$ was also added to the medium. For electron microscopic autoradiography, those oocytes recovered from the culture were washed with phosphate buffer (pH 7.4), and immediately prefixed in a 2.5% glutaraldehyde overnight and postfixed for 2 hours at $4 ^{\circ}C$ in 1% osmium tetroxide in phosphate buffer with pH 7.4 (Palade, 1952). After fixation, the materials were dehydrated in graded alcohol series and embedded in Epon 812 mixture based on the standard procedures (Luft, 1961). The thin sections $600-700{\AA}$ thick were mounted on the grids of 200 meshes. The grids containing sections were coated with a nuclear emulsion Kodak NTB-3 and stored in a cold dark box (at $4^{\circ}C$) for 3 weeks. After exposure, the samples were developed with Kodak D-19 and stained with uranyl acetate and lead citrate. Routine observation was made with Hitachi HU-11E electron microsocope. The results of the observation were as followings: 1. It was found that the labeled dbcAMP penetrated the egg plasma membrane and dispersed at random in the cytoplasm. 2. It was also observed that most of the labeled dbcAMP was attached to microfibrillar lattices portion of the oocyte cytoplasm. There fore, it is presumed that the receptor of the dbcAMP is localized in the microfibrillar lattices of the oocyte. 3. It also seems that some other cell organells such as mitochondria, Golgi complex, cortical granules are not directly related to the action of the dbcAMP. 4. The labeled dbcAMP was neither observed in the membrane nor in the nucleus. Therefore, it seems that there is no relationship between the concentration of dbcAMP and the nuclear membranous permeability. 5. There was no difference in number of dbcAMP particles when oocytes were cultured for 6 hours and 19 hours. 6. However, it was observed that, in same of the oocytes suppressed in germinal vesicle by dbcAMP for 19 hours, cell organells were moved and concentrated to a small portion of the cytoplasm, and that the morphology of the organells greatly changed to an abnormal. form. Therefore, it is supposed that those oocytes were in the process of degeneration. From the above results, it is expected that dbcAMP penetrated the egg membrane and was bound to the receptor which seems to be located in the microfibrillar lattiees portion, and that this dbcAMP-receptor complex inhibited some enzyme system of the oocytes which are essential for the germinal vesicle breakdown.